noun, plural six·teen·mos.
  1. Also called sextodecimo. a book size (about 4×6 in.; 10×15 cm) determined by printing on sheets folded to form 16 leaves or 32 pages.
  2. a book of this size. Symbol: 16mo, 16°
  1. printed, folded, or bound in sixteenmo; sextodecimo.

Origin of sixteenmo

First recorded in 1840–50; sixteen + -mo Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for sixteenmo

Historical Examples of sixteenmo

  • Other sizes occasionally used are called “sixteenmo” or “sextodecimo,” “eighteenmo” or “octodecimo,” etc.

    The Story of Books

    Gertrude Burford Rawlings

British Dictionary definitions for sixteenmo


noun plural -mos
  1. Also called: sextodecimo a book size resulting from folding a sheet of paper into 16 leaves or 32 pages, each one sixteenth the size of the sheetOften written: 16mo, 16°
  2. a book of this size
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for sixteenmo

"book printed on sheets of 16 leaves," 1847, from an English reading of the printers' Latin abbreviation 16-mo, representing sexto decimo "sixteen."

Online Etymology Dictionary, © 2010 Douglas Harper